Users of video hosting systems, such as YOUTUBE, can upload videos for other people to view. Other users can place a video provided by the video hosting system on their web page by embedding or linking to the video sourced by the video hosting system.
The users that upload videos may or may not include a detailed description of the uploaded content. Some video hosting systems display content (e.g., advertising) associated with an uploaded video. Targeting advertisements (ads) to be associated with a video may be difficult if the uploaded video is not accompanied by sufficient metadata (e.g., an attending description). Some systems attempt to directly analyze the content of an uploaded video and select advertisements to display with the video based on this analysis.